Many traditional semiconductor devices have essentially similar shapes: a housing with thin leads extending from it. The housing can be in form of a solid rectangle that serves to enclose and protect the circuitry on the inside. Protruding through the housing are the leads which are used to electrically connect the device to other components or circuits. For example, this form factor is used for some types of insulated-gate bipolar transistor (IGBT).
Because semiconductor devices are used for controlling electric current, their efficiency in doing so play an important role in the efficiency of the overall apparatus where they are being used. For instance, the performance and efficiency of a power inverter—a converter of direct current (DC) to alternating current (AC)—depends on the efficiency of the semiconductors devices in its circuits. The efficiency of the apparatus, in turn, can affect the performance of some larger system. For example, in an electric vehicle (e.g., a plug-in electric vehicle or a hybrid vehicle) the range of travel by electric power before one has to recharge the battery is an important characteristic. Therefore, an improved semiconductor device can improve the performance and efficiency of electric vehicles and other systems.